Chromatography Forum

Dear Group,
I am looking for a suitable internal standard for one of our NCE (Quinazoline), which elutes at 9.0 min in Triethylamine acetate buffer at pH5:MeOH:ACN ::35:10:55 and has absorbance max at 346 nm.Since I developed the HPLC method in simple liquid extraction from plasma for this NCE, i need to find out the suitable internal standard which would possibly elute after 11 min.I would highly appreciate the Group if i can be had the reference of suitable marketed drugs that can be tried with this mobile phase in Hichrom RPB (250*4.6mm) 5µ column as an internal standard.Thanks in advance.

I seem to remember that alkylphenones have been suggested as "general purpose" internal standards. They are commercially available. You simply pick the homolog which comes closest to your desired retention time.

Problem is I can't find a reference. Maybe someone else can chime in here!